In a novel technological breakthrough in neural stimulation, our collaborators at Vanderbilt University have developed a new modality that uses low intensity pulsed infrared laser light instead of electrical energy to elicit compound nerve and muscle potentials. Optical stimulation can induce spatially precise, highly controlled and artifact-free action potentials, generated using energies well below tissue ablation threshold, presenting a paradigm shift in neural activation that has major implications to clinical neural stimulation as well as fundamental neurophysiology and neuroscience. This new modality opens the door to such possibilities as high resolution brain mapping and nerve conduction studies as well as high spatial selectivity in neural resection. While optical stimulation has been validated as a viable method for neural activation, to find its way to practical utility and clinical use, a simple, user friendly, portable, reliable and low cost device must be developed. In this phase 2 proposal, Aculight, in collaboration with Vanderbilt University, Northwestern University, and Washington State University plan to develop an Aculight portable optical stimulator (APOS) for use as a research device for nerve stimulation. The first aim is to develop a prototype APOS with a fiber probe. The second aim is to validate the prototype APOS in peripheral nerve studies. The third aim is to update and evaluate the APOS for facial and Vagal nerve stimulation, cochlear nerve stimulation, and brain slice stimulation. The fourth and final aim is to validate the safety and efficacy of TONS in a clinical setting using the APOS prototype. At the end of this grant period we expect to show the safety and efficacy of an APOS for use in a research setting that will be ready for pre-production qualification testing. Development of an optical brain/nerve stimulator Project Narrative Transient Optical Nerve Stimulation (TONS) provides a new method for scientists to further research and clinical applications involving neural tissue. The advantages of TONS can provide high resolution mapping of neural tissue allowing for less invasive diagnostic procedures that can also lead to fewer surgical risks. [unreadable] [unreadable] [unreadable]